This is the English translation of Announcement.

KDOI Tournament 2026 is here in full force!

The first programming contest in the KDOI Tournament 2026 series, KDOI Tournament 2026 Advanced Round 1, will be held on October 11, 2026, from 18:30 to 22:30 (UTC +8). The contest will feature 4 problems, each worth 100 points, with a total duration of 4 hours. It will follow the traditional OI contest format.

This will also be the first rated contest on OICon OJ! Advanced Round 1 is open to participants with a rating below 2400. Since this is the first contest on our online judge, however, everyone is eligible to participate.

The staff involved in organizing this contest are:

• Problem setters: Error_Yuan and sszcdjr;
• Testers: Anonyme, qhj0906, HHH666666, and caibyte.

Let us thank them for all their hard work!

What Is the Traditional OI Contest Format?

For participants who are unfamiliar with the traditional OI contest format, here is a brief explanation:

Each problem is worth 100 points. For most problems, points are awarded separately for each test case, with all test cases carrying equal weight. For example, if a problem contains 25 test cases, each test case will be worth 4 points. Any exceptions will be stated explicitly. Only your last submission for each problem will be judged.

During the contest, your code will not be run directly against the final test data. Instead, a set of sample test cases will be provided for each problem, and your code will be run against those samples. Unlike Codeforces, AtCoder, and XCPC contests, these problems will generally include a larger number of samples covering a variety of constraint categories. You will be able to download them from the Attachments section of each problem.

To make the contest more exciting, a leaderboard will be displayed during the contest. Each sample test case is worth 1 point, which is awarded only if your solution passes that sample completely. The maximum leaderboard score for each problem is therefore equal to the number of samples provided for that problem. The leaderboard will be frozen during the final hour of the contest and will no longer be updated after the freeze.

Final judging will begin approximately five minutes after the contest ends. The leaderboard will then be unfrozen, and the final judging process will be broadcast live. The official contest results will be determined by the final judging.

Is AI Allowed During the Contest?

The use of AI in any form is strictly prohibited throughout the KDOI Tournament series. This includes, but is not limited to, using AI-powered code completion or obtaining solution ideas from AI. Any participant found violating this rule will have their account banned immediately. If you discover any form of AI usage, please report it to us in the comments on this blog post.